Messages in this thread | | | Date | Fri, 23 Feb 2001 13:44:14 -0800 | From | "H. Peter Anvin" <> | Subject | Re: cpu_has_fxsr or cpu_has_xmm? |
| |
Quim K Holland wrote: > > DL> As to the correctness, the mxcsr register really only exists > DL> if you have xmm, so the xmm is the correct test. However,... > > DL> ... User space programmers should be checking for xmm > DL> capability themselves before ever paying attention to mxcsr > DL> anyway, so it's not an end of the world error. > > If that is the case, wouldn't it be simpler to always return > tsk->thread.i387.fxsave.mxcsr from this function, and initialize > that field to 0x1f80 (whatever that magic number means) when > the structure is built? >
No, because the CPU *may* overwrite it when you do an FXSAVE.
-hpa
-- <hpa@transmeta.com> at work, <hpa@zytor.com> in private! "Unix gives you enough rope to shoot yourself in the foot." http://www.zytor.com/~hpa/puzzle.txt - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |